Methods and Apparatus for Preamble Detection in A Communication Network

ABSTRACT

Methods and apparatus for preamble detection in a communication network are disclosed. In an exemplary embodiment, a method includes retrieving parameters from a parameter database, filling a buffer of preamble data received in an uplink transmission from user equipment, and frequency shifting the buffer of preamble data based on one or more first parameters to generate frequency shifted data. The method also includes oversampling the frequency shifted data to generates oversampled data, downsampling the over sampled data based on one or more second parameters to generate preamble samples, and updating the parameter database with updated values for the one or more first and second parameters. The method also includes repeating all the operations until a selected amount of preamble samples is obtained.

PRIORITY

This patent application is a continuation patent application of aco-pending U.S. patent application having a U.S. patent application Ser.No. 17/233,405, filed on Apr. 16, 2021 in the name of the same inventorand entitled “Methods and Apparatus for Preamble Detection in ACommunication Network,” which further claims the benefit under 35 U.S.C.§ 119 of U.S. Provisional Patent Application No. 63/011,196 filed onApr. 16, 2020 and entitled “Rate Converter for Preamble Detection in4G/5G Basestation System-on-Chip (SoC),” all of which are herebyincorporated herein by reference in their entirety.

FIELD

The exemplary embodiments of the present invention relate tocommunication networks. More specifically, the exemplary embodiments ofthe present invention relate to receiving and processing data streamsvia a wireless communication network.

BACKGROUND

High speed communication networks, such as fourth generation (4G) longterm evolution (LTE) and fifth generation (5G) new radio (NR) networksare becoming increasingly utilized to communicate data between userequipment. To communicate over these networks, a user equipment firstneeds to acquire access privileges. In 4G LTE/5G NR systems, multipleformat access preambles can be transmitted in uplink transmissions fromuser equipment to obtain access privileges from the network. Each accesspreamble format has its own sample rate and bandwidth. Typically, a basestation receiver needs many instances of a preamble detector, which aresimultaneously running at each carrier frequency to detect the receivedpreambles.

Therefore, it is desirable to have a system to perform preambledetection in a fast and efficient manner.

SUMMARY

In various exemplary embodiments, methods and apparatus for preambledetection are disclosed.

In an exemplary embodiment, a method is provided that comprisesretrieving parameters from a parameter database, filling a buffer ofpreamble data received in an uplink transmission from user equipment,and frequency shifting the buffer of preamble data based on one or morefirst parameters to generate frequency shifted data. The method alsoincludes oversampling the frequency shifted data to generatesoversampled data, downsampling the over sampled data based on one ormore second parameters to generate preamble samples, and updating theparameter database with updated values for the one or more first andsecond parameters. The method also includes repeating all the operationsuntil a selected amount of preamble samples is obtained.

In an exemplary embodiment, apparatus is provided that comprises aprocessor and a memory configured to perform operations of: retrievingparameters from a parameter database stored in the memory; filling abuffer of preamble data received in an uplink transmission from userequipment; and frequency shifting the buffer of preamble data based onone or more first parameters to generate frequency shifted data. Theprocessor and the memory are also configured to perform operations of:oversampling the frequency shifted data to generate oversampled data;downsampling the oversampled data based on one or more second parametersto generate preamble samples; updating the parameter database withupdated values for the one or more first and second parameters; andrepeating all the operations until a selected amount of preamble samplesis obtained.

Additional features and benefits of the exemplary embodiments of thepresent invention will become apparent from the detailed description,figures and claims set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

The exemplary aspect(s) of the present invention will be understood morefully from the detailed description given below and from theaccompanying drawings of various embodiments of the invention, which,however, should not be taken to limit the invention to the specificembodiments, but are for explanation and understanding only.

FIG. 1 shows a communication network comprising a transceiver having anexemplary embodiment of a preamble detector configured for accuratedetection of preambles associated with received uplink communications.

FIG. 2 shows an exemplary functional block diagram of the communicationnetwork shown in FIG. 1 ;

FIG. 3 shows an exemplary embodiment of a preamble detector.

FIG. 4 shows an exemplary embodiment of a frequency shifter for use inthe preamble detector shown in FIG. 3 .

FIG. 5 shows an exemplary embodiment of a cascaded integrator-combfilter for use in the preamble detector shown in FIG. 3 .

FIG. 6 shows an alternative exemplary embodiment of a preamble detector.

FIG. 7 shows an exemplary embodiment of a parameter database for usewith embodiments of a preamble detector.

FIG. 8 shows a method for detecting a preamble in a received uplinktransmission in accordance with embodiments of the present invention.

DETAILED DESCRIPTION

In various exemplary embodiments, methods and apparatus for preambledetection in a communication network are disclosed.

The purpose of the following detailed description is to provide anunderstanding of one or more embodiments of the present invention. Thoseof ordinary skills in the art will realize that the following detaileddescription is illustrative only and is not intended to be in any waylimiting. Other embodiments will readily suggest themselves to suchskilled persons having the benefit of this disclosure and/ordescription.

In the interest of clarity, not all of the routine features of theimplementations described herein are shown and described. It isunderstood that in the development of any such actual implementation,numerous implementation-specific decisions may be made in order toachieve the developer's specific goals, such as compliance withapplication and business-related constraints, and that these specificgoals will vary from one implementation to another and from onedeveloper to another. Moreover, it will be understood that such adevelopment effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of engineering for those ofordinary skills in the art having the benefit of the embodiments of thisdisclosure.

Various embodiments of the present invention illustrated in the drawingsmay not be drawn to scale. Rather, the dimensions of the variousfeatures may be expanded or reduced for clarity. In addition, some ofthe drawings may be simplified for clarity. Thus, the drawings may notdepict all of the components of a given apparatus (e.g., device) ormethod. The same reference indicators will be used throughout thedrawings and the following detailed description to refer to the same orlike parts.

FIG. 1 shows a communication network 100 comprising a transceiver 116having an exemplary embodiment of a preamble detector (PD) 118configured for fast and accurate detection of preambles associated withreceived uplink communications. The communication network 100 includes abase station 114 that includes the transceiver 116. The transceiver 116has a transmitter portion 128 and a receiver portion 130. The basestation 114 is configured to communicate with radio towers 110A-Clocated in cell site 102. In various embodiments, the communicationnetwork 100 comprises a 4G LTE or 5G NR communication network. Aspectsof the invention are also suitable for use with other types ofcommunication networks.

User equipment 1 (UE1) 104 transmits uplink communications 120 to thebase station 114 through tower 110 c, and user equipment 2 (UE2) 106transmits uplink communications 122 to the base station 114 throughtower 110 b. For example, the UEs can be smartphones, handheld devices,tablet computers or iPad® devices or any other suitable communicationdevice. It should be noted that the underlying concepts of the exemplaryembodiments of the present invention would not change if one or moreblocks (or devices) were added or removed from the communication network100.

Each user equipment transmits an access preamble to acquire accessprivileges to the network. In 4G LTE/5G NR systems, multiple formataccess preambles are utilized and each format has its own samplerate/bandwidth. To improve the efficient processing of access requestsfrom UEs, the receiver 130 includes the preamble detector 118. Thepreamble detector 118 operates to detect the preamble transmitted in anuplink from each UE. A more detailed description of the PD 118 isprovided below.

FIG. 2 shows an exemplary functional block diagram 200 of thecommunication network 100 shown in FIG. 1 . Each user equipment 202A-Ntransmits signals to the receiver 130 through an uplink transmission. Toaccess the network, each user transmits an access preamble 204A-N. Invarious exemplary embodiment, the preamble detector 118 operates toprovide efficient detection the access preamble received from each UE.

FIG. 3 shows an exemplary embodiment of a preamble detector 300. Thepreamble detector 300 is suitable for use as the preamble detector 118shown in FIG. 1 . In an embodiment, the preamble detector 300 comprisesdetector 302, state memory 304, fast correlator 306, signature sequencegenerator 308, and peak detector 310. The detector 302 comprisesfrequency shifter 312, oversampler 314, downsampler 316, and buffer 336.

During operation, the preamble detector 300 processes a selectableamount of received signal samples from one or more UE. In this process,state parameters are stored in the state memory 304 and are used by thefrequency shifter 312 and the downsampler 314. In an embodiment, stateparameters are defined for each virtual receiver set. The detector 302retrieves the state parameters from the state memory 304 when a preambledetection job starts/resumes, and stores updated state parameters in thestate memory 304 after each iteration of the preamble detection jobuntil the job is completed.

In an embodiment, received uplink preamble signals flow through a signalchain comprising the buffer 336, frequency shifter 312, oversampler 314,and downsampler 316. In order to minimize memory usage, the frequencyshifter 312 and downsampler 316 operate on a small number of inputsamples stored in the buffer 336. In doing so, the number of outputsamples is smaller than the number of input samples in most cases, andtherefore the same hardware can be reused multiple times for othervirtual receivers. For example, if the detector is implemented on asystem-on-chip (SoC) device, there is limited space for memory, whichoccupies more space than other processing logic. Furthermore, the costof RAM is related to its size. However, if the SoC has to store theentire received signal for a certain process, it needs a larger memoryto do this. In order to avoid requiring a large memory, the receivedsignal samples are converted as frequently as possible to minimize thebuffer usage. In this implementation, the received signal should bedecimated (e.g., converted to smaller number of samples than the inputsamples in most cases), so that this process is performed as frequentlyas possible. The implementation for doing this process uses piecewisefiltering and decimation as described herein. Therefore, to avoid usinga large buffer as in conventional systems, multiple smaller buffers areused for the filter/decimation process, and a mechanism is provided forstopping and resuming the filter/decimation process whenever it isneeded.

As an example of the reduction in buffer size achieved by embodiments ofthe preamble detector disclosed herein, it will be assumed that a PRACHlong preamble with 839 samples is interpolated to 24576 samples perpreamble (e.g., for 20 MHz LTE/NR bandwidth) and transmitted to thereceiver. On the receiver side, if using the conventional approach, thereceiver would need to buffer the 24576 samples and then decimate thisamount to 2048 samples using a FIR-filter and decimator. However, usingembodiments of the preamble detector disclosed herein, just 2048 samplesare buffered and running the filtering and decimation reduces this tojust 170 samples for each iteration to process a full buffer.

Received uplink data samples 318 are stored in the buffer 336 and theninput to the frequency shifter 312 of the detector 302. In anembodiment, the received data samples 318 are received in a small buffer336 so that the buffer may be re-loaded multiple times to receive thepreamble data. Thus, the detector 300 is configured to processsmaller-sized sample blocks multiple times instead of long sampleblocks. The frequency shifter operates to shift the frequency of thereceived data in order to select the preamble signal at the desiredfrequency to generate frequency shifted data 322. In an embodiment, thefrequency shifter 312 utilizes parameters 320 to perform the frequencyshift. For example, the parameters include an accumulated phase valuethat allows the frequency shifter 312 to operate over multiple buffersof input data. A more detailed description of an embodiment of afrequency shifter is provided with reference to FIG. 4 .

The frequency shifted data 322 is input to the oversampler 314 thatoversamples the data “N” times to generate oversampled data 324. Thedownsampler 316 receives the oversampled data 324 and downsamples thereceived data “M” times to generate downsampled data 328.

In an embodiment, the downsampler 316 comprises a multistage cascadeintegrator comb (CIC) downsampler. The downsampler utilizes selectedparameters 326 from the parameters database 304 to perform thedownsampler operation. For example, the parameters include an inputsample count and filter states represented by accumulator values in theCIC filter for all stages. A more detailed description of an embodimentof a downsampler is provided with reference to FIG. 5 . Once thefrequency shifting and the downsampling are complete for the currentbuffer of received data, updated values for the parameters are storedback into the parameter database 304.

In an embodiment, the detector 302 operates on one or more buffers ofreceived input data 318 to generate enough samples 328 for preambledetection. Once enough output samples from the downsampler aregenerated, the output samples are input to the fast correlator 306. Thecorrelator 306 performs a correlation between the output 328 of thedownsampler 316 and a signature sequence 330 output from the signaturesequence generator 308. Correlation can begin whenever there is asufficient amount of output samples passed from the downsampler 316. Inan embodiment, the time interval between the inputs received from thedownsampler 316 enables almost full utilization of the fast correlator306. The peak detector 310 receives the correlated output 332 andperforms a peak detection to detect the received preamble and generate apreamble output 334

Accordingly, the various embodiments of the preamble detector 300operate to buffer small amounts of received uplink preamble data andthen perform preamble detection over multiple amounts of buffered data.Thus, the detector 300 has low memory requirements as the input bufferis small. The detector 300 also provides almost full utilization of thehardware, and is able to realize almost ideal data throughput withminimum complexity. In contrast, conventional receivers process longsample blocks and utilize multi-stage FIR filters that cannot be stoppedin the middle of the processing job. It is also difficult forconventional systems to reuse the same hardware for multiple detections,since conventional systems have to wait for the previous job to completebefore starting a new one.

FIG. 4 shows an exemplary embodiment of a frequency shifter 400 for usein the preamble detector shown in FIG. 3 . For example, the frequencyshifter 400 is suitable for use as the frequency shifter 312 shown inFIG. 3 . In an embodiment, the frequency shifter 400 comprises anumerically controlled oscillator (NCO) 402 and a complex multiplier404. The NCO 402 comprises an adder 406, phase computation circuit 408,phase conversion circuit 410, and accumulated phase value storage 412.

During operation, the frequency shifter 400 receives complex input data,such as input data 318 that is received from the buffer 336. The inputdata 318 is input to the complex multiplier 404. An accumulated phasevalue, such as accumulated phase value 320 is loaded in the storage 412.The stored accumulated phase value is input to the adder 406. The adder406 also receives a frequency shift input 416 that indicates an amountof frequency shift to be applied. In an embodiment, the frequency shiftinput 416 is generated by an external controller, such as the processor602 shown in FIG. 6 .

The adder 406 adds the values at its inputs to generate a value X at itoutput that is then input to the phase computation circuit 408. Thecircuit 408 determines a phase value Y based on the received X input. Inan embodiment, when (X>π), then (Y=X−2π), when (X<−π), then (Y=X+2π),and when (π>X>−π), then (Y=X).

The computed value Y is input to the phase conversion circuit 410 thatgenerates a complex sinusoid Z based on the received Y input. In anembodiment, the value of Z is determined from (Z=e^(jY)). The value of Zis input to the complex multiplier 404. The complex multiplier 404multiples its inputs to generate a frequency shifted output, such asfrequency shifted output 322 shown in FIG. 3 . The computed Y value,which represents the accumulated phase, is stored in the storage 412.Once the buffer of input data 318 has been phase shifted, theaccumulated phase value 320 in the storage 412. When resuming/stopping adetection job, the accumulated phase value in storage 412 is read fromor written to the parameter database 304.

FIG. 5 shows an exemplary embodiment of a cascaded integrator-comb (CIC)downsampler 500 for use in the preamble detector shown in FIG. 3 . Forexample, the downsampler 500 is suitable for use as the downsampler 316shown in FIG. 3 . In an embodiment, the downsampler 500 comprises combstages 502 and integrator stages 504. The comb stages 502 comprise aplurality of (Z⁻¹) stages 506 a-n connected to a plurality of summationcircuits 508 a-n. The integrator stages 504 comprise a plurality of(Z⁻¹) stages 514 a-n connected to a plurality of summation circuits 512a-n. A controllable switch 510 connects the output of the comb stages502 to the input of the integrator stages 504 based on a sample countvalue 516.

During operation, comb accumulator values (1-n) 518 are loaded into theZ⁻¹ stages 506 a-n, and integrator accumulator values (1-n) 520 areloaded in the Z⁻¹ stages 514 a-n. In an embodiment, the accumulatorvalue 518 and 520 are loaded from parameter database 304 as indicated at326.

Data input 324 is input to the first Z−1 stage 506 a and the firstsummation stage 508 a. In an embodiment, the data input 324 is receivedfrom the oversampler 314 shown in FIG. 3 . The output of each summationstage 508 is input to a subsequent stage until the final summation stage508 n provides its output to the switch 510. The sample count 516 isreceived from the parameter database and controls the switch 510 to passthe output of the comb stages 502 to the input of the integrator stages504. For example, the first summation stage 512 a of the integratorstage 504 receives the output of the comb stages 502 from the switch510. The output of each summation stage 512 is input to a subsequentstage until the final summation stage 512 n provides the downsampledoutput 328. When resuming/stopping a detection job, the comb accumulatorvalues 518 and the integrator accumulator values 520 are read from orwritten to the parameter database 304.

FIG. 6 shows an alternative exemplary embodiment of a preamble detector600. For example, the preamble detector 600 is suitable for use as thepreamble detector 118 shown in FIG. 1 . In an embodiment, the preambledetector 600 comprises processor 602, instructions 606, memory 606,input interface 608, output interface 610, and signature sequences 612,all coupled to communicate over bus 616. In an embodiment, the memorycomprises parameter database 616 and an input data buffer 618.

In an embodiment, preamble data 616 received in uplink transmissionsfrom user equipment is input to the input interface 608. The inputinterface 608 buffers the received preamble data for processing by theprocessor 602.

In an embodiment, the processor 602 executes the instructions 606 toperform the preamble detection functions described herein. For example,the processor 602 performs at least the following operations.

1. Buffer received preamble input data 616 in the buffer 618 until thebuffer 618 is full.

2. Frequency shift the buffer 618 of preamble input data based onparameters 616 stored in the memory 606 to generate frequency shifteddata. For example, the processor 602 performs the functions of thefrequency shifter 400 shown in FIG. 4 . In an embodiment, the processor602 obtains an accumulated phase value (e.g., 320) from the parameters616 and performs the described frequency shifting operations to generatefrequency shifted data.

3. Oversample the frequency shifted data to generate oversampled data.In an embodiment, the processor 602 performs the functions of theoversampler 314 shown in FIG. 3 .

4. Downsample the oversampled data based on parameters 616 stored in thememory 606 to generate preamble samples. For example, the processor 602performs the functions of the downsampler 500 shown in FIG. 5 . In anembodiment, the processor 602 obtains the comb states accumulated values518, integrator accumulated values 520, and the sample count value 516from the parameters 616 and performs the described downsamplingoperations to generate the downsampled data (e.g., preamble samples).

5. Update the parameters 616 in the memory 606. In an embodiment, theupdated parameters for the frequency shifting and downsampling arestored in the parameters database 616 in the memory 606.

6. Determine if there are enough preamble samples. For example, aselected number of preamble samples is used as input to a fastcorrelation process (e.g., fast correlator 306). If there are not enoughpreamble samples, then return to operation (1) to buffer more preambleinput data and perform another iteration. If there are enough preamblesamples, then proceed to operation (7).

7. Correlate the preamble samples with signature sequences 612 togenerate correlated data. In an embodiment, the processor 602 correlatesthe output of the downsampling process (preamble samples) with thesignature sequences 612.

8. Peak detect the correlated data to detect a received preamble. In anembodiment, the processor 602 performs a peak detection process oncorrelation output to identify a selected preamble sequence in thereceived data.

9. Output the detected preamble 618 from output interface 610.

Thus, the preamble detector 600 operates to receive preamble data inuplink transmissions and detect preambles transmitted from userequipment.

FIG. 7 shows an exemplary embodiment of a parameter database 700 for usewith embodiments of a preamble detector. In an embodiment, the database700 is suitable for use as the database 304 shown in FIG. 3 , or thedatabase 616 shown in FIG. 6 . In an embodiment, the database 700comprises frequency shifter parameters 702, which include theaccumulated phase values 320. The database 700 also comprisesdownsampler parameters 704, which include the sample count 516, combaccumulator values 518, and the integrator accumulator values 520. Itshould be noted that the database 700 is exemplary and that otherimplementations are within the scope of the embodiments.

FIG. 8 shows a method 800 for detecting a preamble in a received uplinktransmission in accordance with one embodiment of the present invention.For example, in an exemplary embodiment, the method 800 is performed bythe PD 118 shown in FIG. 1 , the PD 300 shown in FIG. 3 , or the PD 600shown in FIG. 6 .

At block 802, uplink transmissions are received at a receiver from oneor more user equipment. For example, the uplink transmissions includepreamble data that are used to obtain network services for each UE. Theuplink transmission data is stored in an input buffer.

At block 804, a determination is made as to whether an input buffer isfull. For example, the input interface 608 receives uplink preamble dataand stores the data in the buffer 618 of the memory 606. The processor602 determines whether the input buffer 618 in the memory 606 is full.If the buffer 618 is full, the method proceeds to block 806. If thebuffer is not full, the method proceeds to block 802 to receive moreinput data. In an embodiment, the input buffer is the buffer 336 shownin FIG. 3 , which stores input samples until the buffer is full and thenpasses the buffer of input samples to the frequency shifter 312.

At block 806, stored parameters are retrieved from a memory. Forexample, the processor 602 retrieves the parameters 616 from the memory606. The parameters 616 are used to perform frequency shifting anddownsampling. In an embodiment, the parameters used for frequencyshifting are the accumulated phase values 320. The parameters used formdownsampling are the sample count 516, comb accumulator values 518, andthe integrator accumulator values 520.

At block 808, the preamble data is frequency shifted using theparameters to generate frequency shifted data. For example, theprocessor 602 performs this process using one or more of the parameters616. In an embodiment, the frequency shifter 312 performs this processusing one or more parameters 320 of the database 304.

At block 810, the frequency shifted data is oversampled. For example,the processor 602 performs this process. In an embodiment, theoversampler 314 performs this process to generate oversampled data 324.

At block 812, the oversampled data is downsampled. For example, theprocessor 602 performs this downsampling process using the parameterdatabase 616 as described above. In another embodiment, the downsampler316 performs this process using the parameters 326 from the database304.

At block 814, the parameters are updated and stored in the memory. Forexample, the processor 602 performs this process by storing the updatedparameters in the database 616. In an embodiment, the frequency shifter312 and the downsampler 316 store the updated parameters in the database304.

At block 816, a determination is made as to whether there are enoughdownsampled data samples to detect a preamble. For example, theprocessor 602 makes this determination. If there are not enough samples,the method proceeds to block 804 to receive more input data. If thereare enough samples, the method proceeds to block 818. In an embodiment,the buffer 336 outputs data to the frequency shifter 312 when enoughsamples are received.

At block 818, the downsampled data is correlated with signaturesequences. For example, the processor 602 correlates the downsampleddata with the signature sequences 612 to generate a correlated output.In an embodiment, the fast correlator 306 correlates the output of thedownsampler 316 with the signature sequences 330 to generate thecorrelated output 332.

At block 820, peak detection is performed on the correlated data todetect the preamble associated with a particular UE. For example, theprocessor 602 performs peak detection on the correlated output to detectthe preamble. In an embodiment, the peak detector 310 performs the peakdetection on the correlator output 332 to detect the preamble 334.

Thus, the method 800 operates to detect preambles in a received uplinktransmissions. It should be noted that the method 800 is exemplary andthat the operations may be rearranged, added to, deleted, combined, orotherwise modified within the scope of the embodiments.

While particular embodiment of the present invention has been shown anddescribed, it will be obvious to those skilled in the art that, basedupon the teachings herein, changes and modifications may be made withoutdeparting from this exemplary embodiment of the present invention andits broader aspects. Therefore, the appended claims are intended toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of these exemplary embodiments.

What is claimed is:
 1. A method for identifying preamble information ina communication network, comprising: receiving input data containinguplink data samples from user equipment via a communication network;generating downsampled data in accordance with the input data via adetector utilizing parameters stored in a parameter database; generatinga correlated output via operation of correlating selected amount ofdownsampled data in response to a signature sequence; and detecting apreamble in accordance with the correlated output through a performanceof peak detection.
 2. The method of claim 1, further comprisingobtaining the signature sequence from a signature sequence generator. 3.The method of claim 1, further comprising retrieving one or moreparameters from the parameter database to a frequency shifter.
 4. Themethod of claim 1, further comprising storing at least a portion of anuplink transmission in a buffer of preamble data for sampling.
 5. Themethod of claim 1, further comprising generating frequency shifted datavia operation of frequency shifting of buffered preamble data based onone or more parameters.
 6. The method of claim 1, further comprisinggenerating oversampled data through operation of oversampling frequencyshifted data.
 7. The method of claim 1, further comprising generatingpreamble samples via operation of downsampling oversampled data based onone or more parameters.
 8. The method of claim 1, further comprisingupdating values of one or more parameters in response to samplingprocess and storing updated parameters in the parameter database.
 9. Themethod of claim 1, further comprising repeating sampling operationsuntil a selected amount of preamble samples is obtained.
 10. The methodof claim 1, further comprising identifying the signature sequence via amatrix of preamble formats.
 11. The method of claim 1, furthercomprising identifying an accumulated phase value for frequency shiftingfrom the parameters.
 12. The method of claim 1, further comprisingidentifying filter states represented by accumulator values for allstages in a cascaded integrator comb (“CIC”) downsampler from one ormore parameters.
 13. The method of claim 1, further comprisingperforming sample copying for an operation of oversampling.
 14. Themethod of claim 1, further comprising performing downsampling via aprocess of oversampled data with a cascaded integrator comb (“CIC”)downsampler.
 15. A method for detecting preambles in a communicationnetwork, comprising: retrieving one or more parameters from a parameterdatabase and storing the parameters in an accumulated phase valuestorage in a frequency shifter; receiving a frequency shift inputindicating an amount of frequency shift to be applied; generating aninput via adding the frequency shift input and the parameters; andgenerating a frequency shifted data in response to the input and aninput data retrieved from a buffer.
 16. The method of claim 15, furthercomprising determining a phase value based on the input by a phasecomputation circuit.
 17. The method of claim 16, further comprisinggenerating a complex sinusoid value based on the phase value via a phaseconversion circuit.
 18. The method of claim 15, wherein generating afrequency shifted data includes multiplying the input data with acomplex sinusoid value generated by a phase conversion circuit.
 19. Themethod of claim 15, further comprising generating oversampled datathrough operation of oversampling frequency shifted data.
 20. The methodof claim 15, further comprising generating preamble samples viaoperation of downsampling oversampled data based on the parameters. 21.The method of claim 15, further comprising updating values of one ormore parameters in response to sampling process and storing updatedparameters in the parameter database.
 22. The method of claim 15,further comprising repeating sampling operations until a selected amountof preamble samples is obtained.
 23. The method of claim 15, furthercomprising correlating selected amount of preamble samples with asignature sequence to generate a correlated output.
 24. The method ofclaim 23, further comprising performing peak detection on the correlatedoutput to detect a transmitted preamble.
 25. The method of claim 23,further comprising identifying the signature sequence via a matrix ofpreamble formats.
 26. An apparatus for identifying preamble informationin a communication network, comprising: means for receiving input datacontaining uplink data samples from user equipment via a communicationnetwork; means for generating downsampled data in accordance with theinput data via a detector utilizing parameters stored in a parameterdatabase; means for generating a correlated output via operation ofcorrelating selected amount of downsampled data in response to asignature sequence; and means for detecting a preamble in accordancewith the correlated output through a performance of peak detection. 27.The apparatus of claim 26, further comprising means for obtaining thesignature sequence from a signature sequence generator.
 28. Theapparatus of claim 26, further comprising means for retrieving one ormore parameters from the parameter database to a frequency shifter. 29.The apparatus of claim 26, further comprising means for storing at leasta portion of an uplink transmission in a buffer of preamble data forsampling.
 30. An apparatus for detecting preambles in a communicationnetwork, comprising: means for retrieving one or more parameters from aparameter database and means for storing the parameters in anaccumulated phase value storage in a frequency shifter; means forreceiving a frequency shift input indicating an amount of frequencyshift to be applied; means for generating an input via adding thefrequency shift input and the parameters; and means for generating afrequency shifted data in response to the input and an input dataretrieved from a buffer.
 31. The apparatus of claim 30, furthercomprising means for determining a phase value based on the input by aphase computation circuit.
 32. The apparatus of claim 30, furthercomprising means generating a complex sinusoid value based on the phasevalue via a phase conversion circuit.
 33. The apparatus of claim 30,wherein means for generating a frequency shifted data includes means formultiplying the input data with a complex sinusoid value generated by aphase conversion circuit.
 34. The apparatus of claim 30, furthercomprising means generating oversampled data through operation ofoversampling frequency shifted data.
 35. The apparatus of claim 30,further comprising means generating preamble samples via operation ofdownsampling oversampled data based on the parameters.